It sometimes seems as if Poland has perfected its own 20th century version of a medieval ritual. Every couple of months, knights in armor representing rival armies descend on the field of battle. The heralds proclaim "a fight until death," only allowing for one victor, and the world holds its breath.

Then somehow, when battle is about to be joined, the knights are induced to parley with each other. They retreat to a tent, where they are persuaded that such mortal combat can only result in everybody's annihilation. A truce is announced in the name of "the higher interests of the nation," and the world breathes freely again.

After an interval of about four months, Poland's Communist authorities and independent trade union federation Solidarity are once again at loggerheads. Sure enough, the ritual appears to be repeating itself. The spectacle of threats, strikes, negotiations being broken off, appeals for reason and common sense is a familiar one. And, despite some new elements, there is no reason at this point to believe that the current crisis will not also be resolved peacefully.

The Kremlin, meanwhile, has again stepped up its war of nerves, which is bound to have an effect on the party even if most ordinary Poles have ceased worrying about the possibility of invasion. The presence here of Marshal Viktor Kulikov, the Soviet commander of the Warsaw Pact, is presumably related to a Central Committee meeting scheduled for Tuesday. The Polish leaders will no doubt attempt to continue their balancing act, but it is becoming increasingly difficult to satisfy simultaneously the conflicting demands of Moscow and Solidarity.

The more interesting question, which often gets lost in the fascination with daily events, is whether Poland is condemned to a cycle of conflict-truce-conflict that is ultimately self-destructive.

In the West, of course, strikes are regarded as a normal method of settling conflicts. As Poland becomes a more pluralistic society, one would expect strikes and demonstrations to become a natural phenomenon here, too.

In practice, however, as long as the state claims a monopoly of economic and political power, labor unrest inevitably has the character of a trial of strength between authorities and people.

The pretexts for these periodic tests of strength have differed. In October, a symbolic one-hour strike in selected factories was called to protest the government's slowness in implementing the 21-point Gdansk agreement reached after the summer's labor disputes during which Solidarity was formed. The next month there were showdowns over Solidarity's legal registration and the issue of political prisoners.

This year conflicts developed over government promises to introduce a 40-hour working week, the legalization of an independent farmers' union, Solidarity's demands for the removal of corrupt officials and police violence against union activists. To complete the circle, the latest crisis has blown up over food shortages and possible price increases -- the very issue that sparked last summer's strikes and led to the rise of the first independent trade unions in a communist state.

In April, an attempt was made to break out of this vicious cycle when the new premier, Gen. Wojciech Jaruzelski, initiated substantive negotiations with Solidarity. At first, the outlook seemed promising with the registration of Rural Solidarity and the opening of the mass media.

At the same time the underlying power struggle between government and Solidarity was obscured because each was preoccupied with its own internal debates. The Communist Party was preparing for its special congress while Solidarity was engaged in an election campaign of its own, now almost completed.

Finally, the threat of Soviet intervention served to dampen the demands and grievances of ordinary workers and strengthen the hands of moderate Solidarity leaders such as Lech Walesa.

Now the situation has changed. With the congress out of the way, the party feels stronger and more legitimate. Its new, democratically elected leaders are eager to prove to themselves and the Soviet Bloc that they are in control -- and not about to abdicate power to Solidarity.

On Solidarity's side, the pressure on the leadership from the rank and file has increased as Poland's economic problems have worsened. The hardships of everyday life have become less tolerable. While most people realize the government cannot simply stock the shops full of meat, they are demanding concessions in other areas such as Solidarity's own television program.

Today, despite efforts by Solidarity to postpone any protests until after a meeting Monday of the leadership in Gdansk, 5,000 people participated in a hunger march in the southeastern town Krosno.

At times of tension, the extremes on both sides tend to reinforce each other. The radicals in Solidarity believe that only by constant pressure on the authorities can anything be achieved. The conservatives in the party, who still wield considerable influence behind the scenes, also prosper most in conditions of confrontation.

The paradox of Polish politics is that both government and Solidarity have to come right to the brink in order to retreat from it. To avoid disaster, they first have to look it in the face, for it is only then that they can convince their respective supporters of the need for a compromise. It is this political mechanism that has created the impression of a country lurching from crisis to crisis.

The tragedy, of course, is that, with each successive crisis, the underlying problems become more difficult to solve. The economic decline sometimes seems impossible to halt, with exports, imports and production chasing each other downward in a spiral.

On the superficial level, it is not difficult to see a compromise emerging in the Solidarity-government talks interrupted last week amid much mutual recrimination. Some observers fear that the street demonstrations organized by Solidarity represent a dangerous development. In fact, they have been very orderly so far, and there is no evidence that Polish workers have forgotten the hard-won lesson that without discipline they risk losing everything.

The real danger is deeper and was expressed by Deputy Premier Mieczyslaw Rakowski in a speech to last month's party congress.

He warned that the crisis could "assume a permanent character and both the authorities and the public will get used to it. It will become a permanent way of life in which we constantly talk about getting out of the crisis while doing nothing to release ourselves from its grips."

He added: "The threat to our country and national existence need not necessarily have a violent nature. It may instead be gradual, doing the job just as thoroughly . . . . We may get used to the shortage of basic goods and persuade ourselves that work is not what matters most, that other countries must take care of our well-being and that our speciality is celebrations and debates."